1. Field of the Invention
The present invention relates to improvements of a pedal reaction force device that electrically detects a pedaling stroke of an operating pedal and applies a pedaling reaction force to an operating pedal for actuating a hydraulic brake, etc.
2. Discussion of Related Art
An electric pedal device which detects a pedaling stroke of an operating pedal and causes a hydraulic device or an electric motor to execute a prescribed operation has been proposed for a normal brake pedal device for a vehicle. In such an electric brake pedal device, since only a reaction force brought about by a return spring operates and almost no reaction force is produced, there was a problem in that it was difficult for a driver, who is accustomed to a conventional mechanical type pedal device, to carry out a pedaling operation. Therefore, Patent Document 1 proposed a pedal reaction force device for applying a pedaling reaction force having non-linear hysteresis by using a plurality of spring members and dampers, and Patent Document 2 proposed a technology of applying a pedal reaction force by a spring member and simultaneously varying a variation pattern of a pedaling reaction force by electrically detecting vehicle conditions such as a pedaling speed, etc., and displacing the position of a spring retainer by an electric motor.    [Patent Document 1]Japanese Published Unexamined Patent Application No. 2003-261015    [Patent Document 2] Japanese Published Unexamined Patent Application No. 2002-308084